DESCRIPTION: An acute tear of the anterior cruciate ligament (ACL) is one of the more prevalent and debilitating of the 3-17 million sport- and recreation-related injuries that occur each year in the United States. Physical therapy protocols following surgical reconstruction of the ACL have become increasingly aggressive in recent years. There is scant evidence, however, that adherence to these "accelerated" rehabilitation regimens is related to postsurgical outcome. Accordingly, the primary purpose of the proposed study is to examine the relationship between adherence to an accelerated physical therapy protocol and rehabilitation outcome following ACL reconstruction. Secondary purposes of the proposed study are to identify potential demographic and injury-related moderators of the adherence-outcome relationship and to evaluate the correspondence between patient self-report and objective assessment of adherence to a home exercise regimen after surgical reconstruction of the ACL. To accomplish the aims of the study, measures of adherence and outcome will be taken following ACL reconstruction. Self-reports of home exercise completion, objective assessment of home exercise completion, attendance at physical therapy appointments, and practitioner ratings of adherence during physical therapy appointments will be measured for six weeks postsurgery. Rehabilitation outcomes, including range of motion, laxity, functional ability, and subjective symptoms, will be measured preoperatively and at six months, one year, and two years postsurgery. Findings from the proposed study will have implications for rehabilitation practices following ACL reconstruction.